Certification of 1.5 million employees as a class was improper.
Rule 23(a)(2) requires a party seeking class certification to prove that the class has common “questions of law or fact.” Their claims must depend upon a common contention of such a nature that it is capable of class-wide resolution—which means that determination of its truth or falsity will resolve an issue that is central to the validity of each one of the claims in one stroke. Here, proof of commonality necessarily overlaps with respondents’ merits contention that Wal-Mart engages in a pattern or practice of discrimination. The crux of a Title VII inquiry is “the reason for a particular employment decision,” Cooper v. Federal Reserve Bank of Richmond, 467 U. S. 867, 876, and respondents wish to sue for millions of employment decisions at once. Without some glue holding together the alleged reasons for those decisions, it will be impossible to say that examination of all the class members’ claims will produce a common answer to the crucial discrimination question.
603 F. 3d 571, reversed.
10-277 Wal-Mart Stores, Inc., v. Dukes
Scalia, J.; Ginsburg, concurring in part and dissenting in part.